scholarly journals Species- and size-related patterns in stable isotopes and mercury concentrations in fish help refine marine ecosystem indicators and provide evidence for distinct management units for hake in the Northeast Atlantic

2014 ◽  
Vol 71 (5) ◽  
pp. 1073-1087 ◽  
Author(s):  
T. Chouvelon ◽  
F. Caurant ◽  
Y. Cherel ◽  
B. Simon-Bouhet ◽  
J. Spitz ◽  
...  
Keyword(s):  
Fish Species ◽  
Trophic Level ◽  
Trophic Ecology ◽  
Marine Ecosystem ◽  
Feeding Strategies ◽  
Bay Of Biscay ◽  
Management Units ◽  
Δ13c And Δ15n ◽  
Northeast Atlantic ◽  
European Hake

Abstract Recent European environmental policies argue for the development of indicators of the ecological status of ecosystems that are easy to implement and powerful enough to detect changes quickly. For instance, some indicators that are currently proposed for monitoring foodweb structure and functioning are based on the size of organisms, using size as a proxy for trophic level. However, these indicators do not necessarily accurately reflect the underlying trophic structure and dynamics to follow. Ecological tracers (i.e. chemical parameters measured in consumer tissues to infer the trophic ecology of organisms) may serve as complementary indicators of trophic level, and may also help distinguish different populations of a species when more commonly used methods (e.g. genetic, age determination) present their own limitations. Here, we analysed the potential of muscle δ13C and δ15N values and of muscle mercury (Hg) concentrations to depict size-related trophic habits of different fish species. We expected that intra- and interspecific variation in these ecological tracers could be helpful in refining currently proposed indicators of marine ecosystems, and also help in discriminating management unitsfor some species. Four fish species were selected for their economical and/or ecological importance in the Bay of Biscay (Northeast Atlantic): whiting Merlangius merlangus, European hake Merluccius merluccius, Atlantic horse mackerel Trachurus trachurus and anglerfish Lophius piscatorius. Muscle δ13C and δ15N values segregated the species and enabled us to discriminate species-specific feeding strategies with increasing size of individuals. Fish body size was not always linearly correlated with δ15N or trophic level. In contrast, Hg concentrations and size-related Hg patterns were more similar from species to species. Interestingly, muscle δ15N values together with Hg concentrations segregated the two putative stocks of European hake within the Bay of Biscay. Hence, we propose the combined use of ecological tracers as a promising method for accurately assigning a consumer to a trophic guild, investigating Hg trophodynamics in foodwebs, and helping discriminate distinct ecological populations within a species when defining management units.

scholarly journals Ekologi Trofik Komunitas Ikan di Perairan Segara Menyan, Subang, Jawa Barat (Trophic Ecology of the Fish Community in Segara Menyan Coastal Lagoon, Subang, West Java)

2015 ◽  
Vol 20 (3) ◽  
pp. 170 ◽  
Author(s):  
Ahmad Zahid ◽  
M.F. Rahardjo ◽  
Lenny S Syafei ◽  
Rini Susilowati
Keyword(s):  
Temporal Variation ◽  
Fish Species ◽  
Trophic Level ◽  
Coastal Lagoon ◽  
Fish Community ◽  
Trophic Ecology ◽  
Diet Breadth ◽  
Gut Contents ◽  
Trophic Guild ◽  
Spatio Temporal

Pengetahuan mengenai ekologi trofik merupakan dasar dalam memahami ekosistem secara keseluruhan yang dapat dijelaskan melalui pola hubungan trofik interspesies ataupun interserikat. Penelitian bertujuan untuk menjelaskan ekologi trofik meliputi indeks trofik dan jenis makanan dominan, serikat dan tingkat trofik, dan variasi spasial dan temporal komunitas ikan di estuari Segara Menyan. Pengambilan ikan contoh dilakukan setiap bulan pada zona berbeda. Ikan contoh dipisahkan berdasarkan waktu dan lokasi pengamatan, dianalisis isi saluran pencernaannya. Analisa data meliputi indeks vakuitas, jumlah total organisme makanan, jenis makanan dominan, luas relung makanan, dan tingkat trofik.  Pada pengamatan 106 spesies ikan, sebanyak 1-380 saluran pencernaan ikan diamati. Sebanyak lima dari 106 spesies memiliki nilai indeks vakuitas “0” dan jumlah makanan yang dikonsumsi bervariasi mulai dari empat hingga 27 jenis makanan. Secara umum, luas relung ikan adalah rendah berkisar 0,20-0,78 dan kebanyakan berada pada kisaran 0,20-0,48. Zooplankton merupakan jenis makanan paling dominan dikonsumsi oleh ikan. Komunitas ikan dikelompokkan dalam tujuh serikat trofik, yaitu detritivora, fitoplanktivora, zooplanktivora, zoobentivora, moluskivora, krustasivora, dan pisivora. Tingkat trofik komunitas ikan berkisar 2,05-4,73. Faktor perubahan ontogenetik, persediaan makanan, karakteristik habitat, dan ruaya beberapa spesies ikan memengaruhi variasi spasio-temporal jejaring makanan di Segara Menyan. Kata kunci: interaksi trofik, laguna, ikan, variasi spasio-temporal, serikat trofik Knowledge of trophic ecology is one way to understanding the whole ecosystem which explained by trophic relationship pattern (interspecies or interguild). The objective research was described of the trophic ecology, i.e. trophic index and dominant prey, trophic guild and trophic level, and spatio-temporal variation of fish community in Segara Menyan coastal lagoon. Fish were collected monthly for one year at three zones. Fish samples were placed in separate labelled plastic bags according to the time scale and location sampling, then gut contents were analyzed. The data of vacuity index, number of prey, prey dominant, diet breadth, and trophic level were analyzed. For each of 106 fish species, between 1 and 380 stomachs, were examined. The vacuity index was also different among species. Five of 106 species had a vacuity index of “0” and total number of food items consumed varied between fish species, ranging from three items to 27 items. The overall diet breadth (Bi) was relatively low among species, ranging from 0.20 to 0.78, with most of them between 0.20 and 0.48. Calanoid copepods comprised the most common food item consumed by all the fishes examined. Fishes occurring can be broadly categorized into seven different trophic guilds. The trophic level of fish communities ranged from 2.05 to 4.73. Spatio-temporal variation of food web was influenced of ontogenetic shift, food availability, habitat characteristic, and migration of some species in Segara Menyan coastal lagoon. Keywords: trophic interaction, lagoon, fishes, spatio-temporal variation, trophic guild

Trophic ecology of the blue shark (Prionace glauca) based on stable isotopes (δ13C and δ15N) and stomach content

2015 ◽  
Vol 96 (7) ◽  
pp. 1403-1410 ◽  
Author(s):  
Sandra Berenice Hernández-Aguilar ◽  
Ofelia Escobar-Sánchez ◽  
Felipe Galván-Magaña ◽  
Leonardo Andrés Abitia-Cárdenas
Keyword(s):  
Stable Isotope ◽  
Stomach Content ◽  
Trophic Ecology ◽  
Baja California ◽  
Marine Ecosystem ◽  
Isotope Analysis ◽  
Trophic Levels ◽  
Baja California Sur ◽  
Δ13c And Δ15n ◽  
Prionace Glauca

Occupying the upper levels of trophic webs and thus regulating prey at lower levels, sharks play an important role in the trophic structure and energy dynamics of marine ecosystems. In recent years, the removal of these individuals from upper trophic levels as a result of overfishing has negatively affected ecosystems. We analysed the diet of blue sharks (Prionace glauca) caught off the west coast of Baja California Sur, Mexico, during the months of February–June in 2001, 2005 and 2006. We employed both stomach content and stable isotope analyses as each method provides distinct yet important information regarding the role of blue sharks in marine food webs, allowing us to estimate the relative contribution of different prey items to this predator's diet. Of the 368 stomachs analysed, 210 contained food (57%) and 158 (43%) were empty. Based on stomach contents and the index of relative importance (IRI), the pelagic red crab (Pleuroncodes planipes) was the most important prey, followed by the squids Gonatus californiensis (34.1%) and Ancistrocheirus lesueurii (10.4%). The mean (±SD) values for δ15N (16.48 ± 0.94‰) and δ13C (−18.48 ± 0.63‰) suggest that blue sharks prefer feeding in oceanic waters. The trophic level based on stomach content analysis was 4.05, while that based on the stable isotope analysis was 3.8, making blue sharks top consumers in the marine ecosystem of Baja California Sur, Mexico.

scholarly journals Distribution of mercury species in different tissues and trophic levels of commonly consumed fish species from the south Bay of Biscay (France)

2021 ◽  
Vol 166 ◽  
pp. 112172
Author(s):  
Tiphaine Mille ◽  
Amaëlle Bisch ◽  
Nathalie Caill-Milly ◽  
Pierre Cresson ◽  
Jonathan Deborde ◽  
...  
Keyword(s):  
Fish Species ◽  
Trophic Levels ◽  
Mercury Species ◽  
Bay Of Biscay ◽  
The South ◽  
Different Tissues

scholarly journals Diversity and Diet Differences of Small Mammals in Commensal Habitats

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 346
Author(s):  
Linas Balčiauskas ◽  
Laima Balčiauskienė ◽  
Andrius Garbaras ◽  
Vitalijus Stirkė
Keyword(s):  
Small Mammals ◽  
Small Mammal ◽  
Trophic Ecology ◽  
Mammal Species ◽  
Additional Food ◽  
Δ13c And Δ15n ◽  
Degree Of Separation ◽  
Kitchen Gardens ◽  
Dietary Plasticity ◽  
The Stability

The stability of diversity of syntopic (inhabiting the same habitat in the same time) small mammals in commensal habitats, such as farmsteads and kitchen gardens, and, as a proxy of their diet, their isotopic niches, was investigated in Lithuania in 2019–2020. We tested whether the separation of species corresponds to the trophic guilds, whether their diets are related to possibilities of getting additional food from humans, and whether their diets are subject to seasonal trends. We analyzed diversity, dominance and distribution of hair δ13C and δ15N values. Diversity and dominance was not stable and differed according to human influence. The highest small mammal species richness occurred in commensal habitats that provided additional food. The degree of separation of species was higher in homestead habitats than in kitchen gardens, where a 1.27 to 35.97% overlap of isotopic niches was observed between pairs of species. Temporal changes in δ13C and δ15N values in the hair of the mammals were not equally expressed in different species. The isotopic overlap may depend on dietary plasticity, minimizing interspecific competition and allowing co-existence of syntopic species. Thus, small mammal trophic ecology is likely related to intensity of agricultural activities in the limited space of commensal habitats.

scholarly journals Trophic ecology of Lontra longicaudis (Carnivora, Mustelidae) in lotic and semilotic environments in southeastern Brazil

2012 ◽  
Vol 102 (3) ◽  
pp. 261-268 ◽  
Author(s):  
Lívia B. Santos ◽  
Nelio R. dos Reis ◽  
Mário L. Orsi
Keyword(s):  
Fish Species ◽  
Food Habits ◽  
Trophic Ecology ◽  
Hydroelectric Power Plant ◽  
Southeastern Brazil ◽  
Aquatic Animal ◽  
Hydroelectric Power ◽  
Exotic Fish ◽  
Lotic Environment ◽  
Lontra Longicaudis

Lontra longicaudis (Olfers, 1818) (Carnivora, Mustelidae) is a semi-aquatic animal spread through the Central and South America, except in Chile. The implantation of a hydroelectric power plant along a river alters the dynamics of the watercourse, transforming a lotic environment into a lentic or semilotic one, what can damage the otter's feeding. From April 2008 to March 2009 we analysed the otter's food habits in lotic (streamlet) and semilotic (hydroelectric reservoir) environments of Paranapanema Valley, in southeastern Brazil. Aiming to compare the otter's diet of these two environments, we analyzed statistically the frequency of occurrence of main items in the scats. Fishes represent the base of the diet both in the reservoir and in the streamlet and, despite of the total otter's diet showing up similarities in the two environments, the results evidenced modifications on the fish species consumed between them. In the reservoir the otters ate more exotic fish Oreochromis niloticus (Linnaeus, 1758) probably because it is an easy capture prey in this place. The fact that the otters get established and feed in the reservoir doesn't mean that this structure is benefic to the species because the food supplied for it consists mainly of exotic fish species.

scholarly journals Analysis of reproductive biology and spawning season of the pink ear emperor Lethrinus lentjan, from marine ecosystem

2020 ◽  
Vol 37 ◽  
pp. 1-10
Author(s):  
Elsayed M. Younis ◽  
Nasser A. Al-Asgah ◽  
Abdel-Wahab A. Abdel-Warith ◽  
Mohamed H. Gabr ◽  
Fozi S. Shamlol
Keyword(s):  
Fish Species ◽  
Gonadosomatic Index ◽  
Marine Ecosystem ◽  
Local Population ◽  
Spawning Season ◽  
Monthly Basis ◽  
Population Sampling ◽  
Maturation Rate ◽  
Maturation Index ◽  
One Year

A total of 593 samples of Lethrinus lentjan (Lacepede, 1802) were collected from the Red Sea, Jeddah, Saudi Arabia, to study their productive biology and spawning season of the local population. Sampling was carried out on a monthly basis for a period of one year. The monthly sex ratios indicated that females were dominant throughout the study period, with an overall male:female sex ratio of 1:7.98, although males were larger than females. The highest monthly performance maturation index (PMI), as well as the male and female gonadosomatic index (GSI) and ovarian maturation rate (OMR) were observed in February and March. Histological examination of the gonads confirmed the process of sexual transformation in this fish species, wherein individuals mature first as female, and then change sex to male (protogynous hermaphroditism). Histological sections also showed that the sexual maturation of males of L. lenjtan comprised three main stages, while the sexual development of females could be classified into four main stages. Extended spawning in the form of batches released during different months throughout the year were recorded for this fish species, with the main spawning season in February and March, and an additional, shorter spawning season in September.

scholarly journals eDNA metabarcoding as a biomonitoring tool for marine protected areas

2020 ◽  
Author(s):  
Zachary Gold ◽  
Joshua Sprague ◽  
David J. Kushner ◽  
Erick Zerecero ◽  
Paul H. Barber
Keyword(s):  
Protected Areas ◽  
Fish Species ◽  
Marine Protected Areas ◽  
Marine Reserve ◽  
Marine Ecosystem ◽  
Site Occupancy ◽  
Visual Methods ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Promising Alternative

AbstractMonitoring of marine protected areas (MPAs) is critical for marine ecosystem management, yet current protocols rely on SCUBA-based visual surveys that are costly and time consuming, limiting their scope and effectiveness. Environmental DNA (eDNA) metabarcoding is a promising alternative for marine ecosystem monitoring, but more direct comparisons to visual surveys are needed to understand the strengths and limitations of each approach. This study compares fish communities inside and outside the Scorpion State Marine Reserve off Santa Cruz Island, CA using eDNA metabarcoding and underwater visual census surveys. Results from eDNA captured 76% (19/25) of fish species and 95% (19/20) of fish genera observed during pairwise underwater visual census. Species missed by eDNA were due to the inability of MiFish 12S barcodes to differentiate species of rockfishes (Sebastes, n=4) or low site occupancy rates of crevice-dwelling Lythrypnus gobies. However, eDNA detected an additional 30 fish species not recorded in paired visual surveys, but previously reported from prior visual surveys, highlighting the sensitivity of eDNA. Significant variation in eDNA signatures by location (50m) and site (~1000m) demonstrates the sensitivity of eDNA to address key questions such as community composition inside and outside MPAs. Interestingly, eDNA results recorded higher species richness outside the MPA while visual surveys observed the opposite pattern. This result is likely caused by swamping effects of high fish abundance in MPAs that reduce detection probabilities of pelagic and intertidal taxa. Results demonstrate the utility of eDNA metabarcoding for monitoring marine ecosystems, providing an important complementary tool to visual methods.

scholarly journals Resource partitioning and ecomorphological variation in two syntopic species of Lebiasinidae (Characiformes) in an Amazonian stream

2016 ◽  
Vol 46 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Nathália Carina dos Santos SILVA ◽  
Aluízio José Lopes da COSTA ◽  
José LOUVISE ◽  
Bruno Eleres SOARES ◽  
Vanessa Cristine e Souza REIS ◽  
...  
Keyword(s):  
Resource Partitioning ◽  
Trophic Ecology ◽  
Species Coexistence ◽  
Stomach Contents ◽  
Relative Length ◽  
Niche Overlap ◽  
The Body ◽  
Feeding Strategies ◽  
Relative Depth ◽  
Feeding Niche

ABSTRACTResource partitioning is important for species coexistence. Species with similar ecomorphology are potential competitors, especially when phylogenetically close, due to niche conservatism. The aim of this study was to investigate the resource partitioning among populations of two species of lebiasinids (Copella nigrofasciata and Pyrrhulina aff. brevis) that co-occur in a first-order Amazonian stream, analyzing the trophic ecology, feeding strategies and ecomorphological attributes related to the use of food and space by these species. Fish were captured in May and September 2010. The stomach contents of 60 individuals were analyzed and quantified volumetrically to characterize the feeding ecology of both species. Eleven morphological attributes were measured in 20 specimens and combined in nine ecomorphological indices. Both species had an omnivorous-invertivorous diet and consumed predominantly allochthonous items. Both showed a tendency to a generalist diet, but intrapopulational variation in resource use was also detected. Overall feeding niche overlap was high, but differed between seasons: low during the rainy season and high in the dry season. In the latter, the food niche overlap was asymmetric because C. nigrofasciata consumed several prey of P. aff. brevis, which reduced its food spectrum. The ecomorphological analysis suggests that C. nigrofasciatahas greater swimming capacity (greater relative length of caudal peduncle) than P. aff. brevis, which has greater maneuverability and tendency to inhabit lentic environments (greater relative depth of the body). Our results demonstrate that these species have similar trophic ecology and suggest a spatial segregation, given by morphological differences related to locomotion and occupation of habitat, favoring their coexistence.

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